Things can really get thorny, though, when someone is covered by both a college plan and mom and dad's insurance.

For those covered by more than one plan, getting in-network care may hinge on which plan is considered to be the primary one.

Young Invincibles, an advocacy group for young people, is beginning to work with the National Association of Insurance Commissioners to update a model regulation that addresses the coordination of benefits problem for young people with more than one insurance plan, says Jen Mishory, the organization's deputy director.

Without clear rules that spell out which plan takes the lead regarding provider networks, a young person who lives out of state and is covered by his parents' plan and a college health plan, say, or by health insurance through his job, might run into trouble trying to get in-network care when far from his parents' regional network.

That can mean he would be on the hook for a bigger share of the costs. Using out-of-network providers can also expose people to higher maximum out-of-pocket limits and balance billing by providers, among other things.

Likewise, a student covered by her parents and a college plan who is home visiting mom and dad over the holidays could get tripped up if she got sick far from her college coverage area.

On the plus side, a young person who is covered by two plans may be able to get more benefits covered, if the secondary plan "wraps around" the primary plan and fills in where the primary plan's coverage ends.

Working with the NAIC, Young Invincibles is trying to figure out "how we can coordinate those benefits so that everyone knows what their rights are, and help consumers access their benefits most affordably," says Mishory.